Elecraft ax2 vs mfj 1820t antenna

Let’s say I want to buy the AX1, the 40m extension, a tripod adapter and a 4m radial … at current prices in Europe and with shipping this will set me back “only” 256.90 Euro (280 USD). Wow!

I can make a link dipole, a non-resonant endfed with two different lenghts of wire and a 9:1 unun, a resonant endfed with a 49:1 unun and lenghts of wire for all HF bands I can think of, add a fishing pole, coax, some rope and some stakes … and still have lots of money in my pocket.

And I will put a decent signal on the air, so that not only the chasers with big antenna’s in quiet rural areas can hear me, but also the poor chasers like me that live in the city, plagued by enormous electro-smog …

Hmm … difficult decision, what should I do? :wink:

But am I against such a whip antenna ?
No, of course not, I carry this ‘emergency’ antenna with my KX3 all the time, since long before the AX1/2 were available. I add a 4m CP with a big crocodile clip (not in the picture).
I once worked Michael @DB7MM/P with it from a local park, using only 2.5W on 20m SSB (and from Belgium, that is quite an achievement on such short skip).

73,
Luc ON7DQ

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Funny thing is, Heinz, I was making exactly your counter argument (to what I said above) to my wife just before reading your post. I certainly don’t want to be a party pooper and spoil anyone’s fun.

Explaining it to her, I was saying I think it’s mainly a ‘man thing’ - we love high-performance techy stuff especially if it’s small and lightweight, e.g. I really like my KX2. And if someone has the discretionary income to spend on ‘boys toys’ that’s fine with me [I did it quite often before I retired].

I chipped in to this conversation only after reading about suggestions to improve the performance of a short HF whip by adding a long elevated counterpoise, which hardly meets the needs of pedestrian mobile, ‘stealth’ or confined space operation.

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Hi Heinz,

I’m certainly not against anyone having fun and learning as they go.To the contrary I encourage that.

Note that the Elecraft manual says you need to use the tuner and-
Always use at least one radial (included). This improves
transmit signal radiation by up to 20 dB, and reduces the risk of
getting an RF burn from the mic, key, or chassis.

Doesn’t hurt to read the manual carefully.

There is a nice video floating about by the Spanish Elecraft Agent using a KX2 and AX2 plus a radial on a peak working many stations. Sorry I cant find the link.

So long as people do understand that its not a serious dx antenna, that there is no magic or miracle bestowed on the owner, then that’s fine. Yes, given the right conditions an occasional US station can be worked from Europe on 20m. Using a second wire instead of the whip is going to be better.

If I’m not getting contacts I’m not having fun.

While some may want to use a tiny whip as their main antenna and that’s their choice, I would consider one of these antennas only as an emergency device, to be put in the bottom of the rucksack along with the snake bite bandage.

YMMV.

73
Ron
VK3AFW

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I have to say, the clear perspex sleeve on Karl’s AX2 is now rotating freely around the coil and switches, so I wouldn’t say the construction warrants such a massive premium. If I was serious about verticals, I would probably use the triband kit from QRPGUYS and add in some resonant elevated radials:

        73 de OE6FEG
                  Matt
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If that means the AX1 with 1 band switch, then here’s a (constructive) contribution to what I see as a minor, if any, imperfection of the AX1:
https://elecraft-kx.groups.io/g/main/topic/89682579#71684

BTW, given the level of detail the AX2’s design and build is documented in the user’s manual (hats off Elecraft!), cheap copies will probably soon be available on ebay, free shipping of course.

Sorry, I stand corrected. It is the AX1 Karl has. I will try screwing it back together next time I see Karl.
73 Matt

As a homebrewer that experiments making antennas, I am already playing around trying to reproduce it for fun. I doubt I would ever activate with it. So far it is a challenge getting the toroid wraps near perfect.

Malen
VE6VID

Some more testing today. Hooked up the ax2 and mfj to the kx2 and the results are as follows

Ax2 swr 1:1
Mfj swr 2:1

I can’t explain it lol

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If the setup was not identical to the previous day then readings may well be different.

Can you explain how you have the antennas setup and how you are measuring SWR?

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You’re right. I’m using it handheld. And my body is causing fluctuations, depending on how I stand the swr changes dramatically. The kx2 is more in the open then the 817 when using it handheld.

AJ,

I did do some quick testing on the MFJ antenna (very non-scientific), and the single test sample did work. I used radials for each band joined to an alligator clip and clipped to the 817. I was able to make a contact across South Carolina to a fellow using a dipole (on CW, of course).

Big takeaway was spread the radials a bit and don’t cross them. Once I had a good SWR/reactance reading on each band (using MFJ-259), I wrote down (for each band) the number of whip elements extended plus the number of finger widths on a partial element. That’ll obviously change due to environment, but it’s a starting place.

Again, this was only one attempt with one contact on one band (80m), but that’s an excuse to find time to test the other bands. It’s definitely a compromise antenna, but the testing was fun and it might work in a pinch or when not much time available. I will be making radials for the single bands (2 per band as mentioned earlier in the thread), having them all together is a real rats nest.

More details at the link below.

73, and good luck. Have fun with the testing.

Mike, N4VBV

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Just if someone should be interested: I have already used the AX2 comprise antenna for SOTA activations on 20m. I have exclusively bought the antenna for cold winter operations or for walks with my wife where I only have 15 - 20 minutes to set up my station / antenna, and to make contacts. Given the weight and size of the AX2, these goals are easily achieved. No need to carry a pole with you that saves at least 500g. AX2 and KX2 fit in one pocket. At the end, it all depends on the conditions and the chasers that are around. The AX2 is not my first choice, but if things must go quickly and if size / weight matters, the antenna fits the bill. 73 de Chris, DL1GKC

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I have a MFJ 1840T and has a lot of SWR, with or without counterpoise.

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